“We hope that the employers will finally be responsive to our demands.”

Frankfurt is the main hub for Germany’s biggest airline, Lufthansa. The airline said earlier that passengers with a flight from Frankfurt can rebook for free onto another flight until January 20.

Ver.di said it is still waiting for employers to increase the pay of 23,000 security staff conducting checks and is demanding that their hourly rates rises to 20 euro (£18).

The strikes have led to the cancellation of flights (Christian Charisius/dpa via AP)

Employers association BDLS says this could amount to a 30% increase in some cases.

“Again, the trade dispute is being carried out on the backs of hundreds of thousands of passengers, the airlines and many other companies belonging to the German tourism industry,” said Michael Rabe, the general secretary of the Federal Association of the German Tourism Industry.

Last week, strikes across Germany resulted in the cancellation of hundreds of flights.